Question

explain critical angel and obtain an expression of it ​

Answer 1

Answer:

Critical angle for a boundary between 2 surfaces depends on the ratio of refractive indices of the media. Refractive index is inversely proportional to the velocity of light in that medium. For finding the critical angle (x) we use the following equation:

n₁∗sin(x)=n₂

n₁/n₂=v₂/v₁ (since they are inversely proportional)

=>v₂∗sin(x)=v₁

=>x=sin⁻¹(v₁/v₂)

This equation can be used to find the critical angle when a light incident from medium 1 onto the boundary between the medium 1 and 2.

Explanation:

Answer 2

Answer:

critical angle is the angle of incidence where angle of refraction is 90 degree